Were did that Marantz 300dc come from?

Hyjack it all you want, thats what were here for. I too am impressed with your Fine set of gear. I have always been a receiver guy but the more i look at the separates out there the more i think of picking up a tuner and pre amp.

Thanks. I've always been a receiver guy as well, but this place has had an effect on me...and my bank account. I did keep my 2285B and 5030 cassette deck for my bedroom setup.

One question i have is knowing how to match a pre amp to an amp like the 300dc. Right now all i have is the pre amps out of the (2325) and i literally mean out of the receiver:D

what is the criteria for matching them?

As far as matching them, I used this site and scrolled through a lot of threads on this site. I stumbled across the 3250B, so I bought it. I can't find and probably couldn't afford the 3650.
 
BTW...there's a fine 2100 tuner listed right now in the Barter Town forum. $100 + fees and shipping. That's a fraction of what I paid for my 2130.
 
Well Jennie is going to kick my Ass, But i bought a 300dc today. :banana:
I will post pictures when it arrives in the mail.

$800 with rack handles. Its not mint, but i'm buying it to power up the Transmission shop speakers from the 2325 pre amp. I will have to rebuild it first to cure a slight hum on one channel.

Thanks to Ron(Jblmar) for his opinion on giving me the push i needed to get one.
I have been wanting one for a while now, but i need it like a hole in my head.
Does anyone have an opinion about these units. I see they are rare. maybe not as rare as a 500.
Thanks, John
John,
1-I too have the Rack Handles (RHA-1). Yes, they're Anodized. $800 for the 300 DC & handles is a great buy. Enjoy!
2-You're welcome. Glad I could help.
 
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BTW...there's a fine 2100 tuner listed right now in the Barter Town forum. $100 + fees and shipping. That's a fraction of what I paid for my 2130.
Bourbon,
I also have the 2130. A great FM tuner!
The 3650 Preamp makes a great combination with the 300 DC & 2130.
 
Thanks, mech! Much better now, and still on track to be eligible to retire in 12 years. I see you're a JBL fan. I've been thinking about upgrading my CV's somewhere down the road. How's about shooting me a PM with your favorite JBLs that will shake the walls - as I know little about them and I don't want to hijack this thread any more than I already have.
Yep! JBL & Marantz. A great combination. Listen to a horn system. !970s or 1980s vintage. You'll be blown away by the sound.
 
I picked up one of these a few months ago. Like yours, not mint, but still looking good enough for my purposes. I'm glad to hear all the positive comments about the 300DC, as I've yet to hook it up. My collection is now complete - except for some custom full wooden cases for all my gear. I'd already have it together but my job was downsized and I was out of work for 3 months. Here's my stack...
12310509_1173524502676284_4460660797707023404_n_zps0xf0a13n.jpg


Enjoy the 300!
Looks similar to my system. The sound of the 2130 is awesome!
 
Thanks Guys, I just read a thread by Ron saying This....
Jblmar Said,.
"Did some measuring the other day on my 300 DC amplifier. Was impressed with the results.
The 300 DC is rated at .03% THD @ 152 WPC. I measured, left channel
.085% THD @ 200 WPC and .075% THD @ 200 WPC for the right channel. Clipping began at around 210 WPC. I backed off to 200 WPC with no sign of onset of clipping.

Channel balance was most impressive. Superimposing the left and right trace revealed no difference in output. I used a 1KHz signal with both Gain controls of the 300 DC full up. I should have switched the Sound Technology 1701A to the dB scale for this measurement. I'll check that next time.

DC offset was < 10 mV for both channels after 1 hour.""
I forgot about that thread. Thanks for posting. I remember how impressed I was with the results.
 
Thanks. I've always been a receiver guy as well, but this place has had an effect on me...and my bank account. I did keep my 2285B and 5030 cassette deck for my bedroom setup.



As far as matching them, I used this site and scrolled through a lot of threads on this site. I stumbled across the 3250B, so I bought it. I can't find and probably couldn't afford the 3650.
Not many 3650s were produced. I had a difficult time getting mine. Bought the 300 DC, 3650 & 2130 in September 1978 . Took the 300 DC & 2130 home that day. The 3650 was another story.
Finally got the 3650 in March 1979. Only 2 units were shipped to Stereo Warehouse here in the NYC area. Another shipped to the West Coast. I ran like hell to get mine. In New York, of course:biggrin:.
 
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Yep! JBL & Marantz. A great combination. Listen to a horn system. !970s or 1980s vintage. You'll be blown away by the sound.

I've been looking around for a pair of Klipsch Cornwalls that are decently priced...with no luck. Now I'm considering a pair of Crites' Cornscalas. His shop is a couple hours away, and I'd like to hear a pair before I bought them.
 
I will keep you in mind if i find a set.I have seen then on Craigslist. Once in a while on ebay. People that own them love them to death.
I was looking into the marantz 400 and 400m. looks like they never really made them. just prototypes. That would be a nice unit to own. i wonder were the prototypes ended up.
0400.jpg
 
I used to own a 300DC. It's a nice amp, great sound. Built like a tank. There is no idle adjustment so if one channel runs hotter you have to change a resistor. Shouldn't have to do anything, but I just mention it.
 
I will keep you in mind if i find a set.I have seen then on Craigslist. Once in a while on ebay. People that own them love them to death.
I was looking into the marantz 400 and 400m. looks like they never really made them. just prototypes. That would be a nice unit to own. i wonder were the prototypes ended up.
0400.jpg
The 400 was a prototype. Never made it to production. I saw this amp in a Stereo Review ad in 1978. I called Marantz about the amp. I was told it was only a prototype.
 
I used to own a 300DC. It's a nice amp, great sound. Built like a tank. There is no idle adjustment so if one channel runs hotter you have to change a resistor. Shouldn't have to do anything, but I just mention it.
Exactly. Changing component(s) is the only way to set the idle current.
 
I received it today and its got a hum alright.
Serious crappy pack job. I can't believe it isn't bent.
Climbing DC. Not good. Pulled the amp board and i am going to go through it starting with the diff pair.
I am going to need sub numbers for some of these transistors. I am going to pull /check
Quick check shows outputs are good.
I would prefer not to change any good transistors unless i have good subs.

I noticed none of the transistors part numbers are ones i am familiar with.
 

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Well there is no going back now....
 

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I received it today and its got a hum alright.
Serious crappy pack job. I can't believe it isn't bent.
Climbing DC. Not good. Pulled the amp board and i am going to go through it starting with the diff pair.
I am going to need sub numbers for some of these transistors. I am going to pull /check
Quick check shows outputs are good.
I would prefer not to change any good transistors unless i have good subs.

I noticed none of the transistors part numbers are ones i am familiar with.
Before tearing into the 300, I would have tracked down and repaired the hum issue. That said, since you already took the amp apart, I would replace all electrolytic capacitors in the amp. As far as the hum is concerned, look at the power supply caps & diodes as well as the large filter caps.
 
Its just the way i work. I'll get it cleaned up. lamps, paper and get the face cleaned up and back on. Then i'll fix it.
On the good side, I found all the transistors on the offending side to check out good.I checked all the diodes and they show to be good also, according to my peak tester. i pulled the newer capacitors and they checked ok. higher esr
I need to find a sub for the diff pair. On this amp it had 2SA879..
Does anyone have a good sub number for these?

The subs used in the past are no longer available unless i buy on ebay, and that is a crapshoot. I'm sure they would most likely work, but i would rather buy confirmed good parts.
 
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Cleaning went well. The faceplate has some marks that will stay. I used pb blaster to get the nicotine off and then used dawn, and ended up using "my cleaning secret". I was originally worried about taking the lettering off, but i did not see any issues in that department. I finished cleaning it and put a coat of coconut oil on it to give it a happy look and smell.
The rear cover was scratched and marred and had rust on the bottom and along the speaker terminals. I sanded it down, ending with wet sand paper. I covered the white lettering with grease and some tape and laid a few coats of flat black rust spray. Its drying. I may need to wet sand it again and recoat. Then i will give it a clear coat sealer.
The chassis was full of stains and some rust that i cleaned using "my cleaning secret" I used cloth so it wouldn't scratch it and that too will get seal coated. i will make sure to clean grounds before bolting important stuff.

I hope, for now, to re-use the filters as long as they check out ok. they look great.
 

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